#!/bin/bash
#------------------------------------------------------------------------------
# =========                 |
# \\      /  F ield         | foam-extend: Open Source CFD
#  \\    /   O peration     | Version:     4.1
#   \\  /    A nd           | Web:         http://www.foam-extend.org
#    \\/     M anipulation  | For copyright notice see file Copyright
#------------------------------------------------------------------------------
# License
#     This file is part of foam-extend.
#
#     foam-extend is free software: you can redistribute it and/or modify it
#     under the terms of the GNU General Public License as published by the
#     Free Software Foundation, either version 3 of the License, or (at your
#     option) any later version.
#
#     foam-extend is distributed in the hope that it will be useful, but
#     WITHOUT ANY WARRANTY; without even the implied warranty of
#     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
#     General Public License for more details.
#
#     You should have received a copy of the GNU General Public License
#     along with foam-extend.  If not, see <http://www.gnu.org/licenses/>.
#
# Script
#     wmakeScheduler
#
# Description
#     Scheduler for network distributed compilations using wmake.
#     - WM_HOSTS contains a list of hosts and number of concurrent processes
#     eg,
#        export WM_HOSTS="hostA:1 hostB:2 hostC:1"
#     - WM_COLOURS contains a list of colours to cycle through
#        export WM_COLOURS="black blue green cyan red magenta yellow"
#
#     Sources the relevant cshrc/bashrc if not set.
#
#     WM_PROJECT_DIR, WM_PROJECT and WM_PROJECT_VERSION will have been set
#     before calling this routine.
#     FOAM_INST_DIR may possibly have been set (to find installation)
#
# Usage
#     wmakeScheduler COMMAND
#         run 'COMMAND' on one of the slots listed in WM_HOSTS
#
#     wmakeScheduler -count
#         count the total number of slots available in WM_HOSTS
#         eg,  export WM_NCOMPPROCS=$(wmakeScheduler -count)
#
#------------------------------------------------------------------------------
lockDir=$HOME/.wmakeScheduler

# fallback - 1 core on current host
: ${WM_HOSTS:=$HOST:1}

# count the total number of slots available and exit
if [ "$1" = "-count" ]
then
    expr $(
        for slotGroup in $WM_HOSTS
        do
            n=${slotGroup##*:}
            [ "$n" = "${slotGroup%%:*}" ] && n=1  # missing ':'
            echo "+ ${n:-1}"
        done
    )
    exit 0
fi

# where to source WM_PROJECT settings in a remote shell
# This code tries to figure out which cshrc or bashrc to execute.
# !! Assumes remote computer running same shell and startup files
# in same location

sourceFoam=false    # fallback command
case $SHELL in
*/csh | */tcsh )    # [t]csh vs bash|ksh|sh
    shellRc=cshrc
    ;;
*)
    shellRc=bashrc
    ;;
esac

# check ~/.$WM_PROJECT/$WM_PROJECT_VERSION/
# check ~/.$WM_PROJECT/
# check <installedProject>/etc/
if [ "$WM_PROJECT" ]
then
    for i in \
        $HOME/.$WM_PROJECT/$WM_PROJECT_VERSION \
        $HOME/.$WM_PROJECT \
        $WM_PROJECT_DIR/etc \
        ;
    do
        if [ -f "$i/$shellRc" ]
        then
            sourceFoam="$i/$shellRc"
            break
        fi
    done
fi

# Construct test string for remote execution.
# Source WM_PROJECT settings if WM_PROJECT environment not set.
# attempt to preserve the installation directory 'FOAM_INST_DIR'
case $sourceFoam in
*/bashrc)
    if [ "$FOAM_INST_DIR" ]
    then
        sourceFoam='[ "$WM_PROJECT" ] || '"FOAM_INST_DIR=$FOAM_INST_DIR . $sourceFoam"
    else
        sourceFoam='[ "$WM_PROJECT" ] || '". $sourceFoam"
    fi
    ;;

*/cshrc)
    # TODO: csh equivalent to bash code (preserving FOAM_INST_DIR)
    sourceFoam='if ( ! $?WM_PROJECT ) source '"$sourceFoam"
    ;;
esac

# quote double-quotes for remote command line
rcmd=$(echo $* | sed -e s/\"/\'\"\'/g)
## the same, without forking (not ksh, maybe not /bin/sh either)
# rcmd=$(while [ "$#" -gt 0 ]; do echo "${1//\"/'\"'}"; shift; done)


# Convert WM_COLOURS into an array
declare colourList
nColours=0
for col in $WM_COLOURS
do
    colourList[$nColours]=$col
    ((nColours = $nColours + 1))
done

# Bashism: make pipe fail early.
# This ensures the return value of the command is returned and not of the
# colouring pipe etc.
set -o pipefail


#
# colour output by argument 1
#
colourPipe()
{
    if [ "$1" ]
    then
    (
        while read line
        do
            setterm -foreground $1
            echo "$line"
        done
        setterm -foreground default
    )
    else
        cat
    fi
}


colourIndex=0

while :
do
    for slotGroup in $WM_HOSTS
    do
        # split 'host:N', but catch 'host:' and 'host' too
        host=${slotGroup%%:*}
        n=${slotGroup##*:}
        [ "$n" = "$host" ] && n=1  # missing ':'
        : ${n:=1}

        i=0
        while [ "$i" -lt "$n" ]
        do
            lockFile="$lockDir/$host:$i"
            if lockfile -r0 "$lockFile" 2>/dev/null
            then
                if [ "$nColours" -gt 0 ]
                then
                    # Set colour
                    colour="${colourList[$colourIndex]}"

                    if [ "$host" = "$HOST" ]; then
                        eval $* 2>&1 | colourPipe "$colour"
                    else
                        ssh $host "$sourceFoam 2>/dev/null; cd $PWD && $rcmd" 2>&1 | colourPipe "$colour"
                    fi
                    retval=$?
                else
                    if [ "$host" = "$HOST" ]; then
                        eval $* 2>&1
                    else
                        ssh $host "$sourceFoam 2>/dev/null; cd $PWD && $rcmd" 2>&1
                    fi
                    retval=$?
                fi

                # Release lock
                rm -f "$lockFile" 2>/dev/null
                exit $retval
            fi
            i=$(expr $i + 1)

            # Cycle through colours. Note: outside lock clause!
            colourIndex=$(expr $colourIndex + 1)
            [ "$colourIndex" -lt "$nColours" ] || colourIndex=0

        done
    done
    # Did not find any free slots. Rest a bit.
    sleep 1
done

if [ "$nColours" -gt 0 ]
then
    setterm -foreground default
fi

#------------------------------------------------------------------------------
